Medical devices that are capable of releasing biologically active agents are desirable in the art. Such medical devices include, for example, stents (e.g., radially expandable stents), grafts, catheters, guide wires, heart valves, bone implants, spinal implants, covered stents, microspheres, and the like, or combinations thereof, that are inserted in a body during use. Such devices that release biologically active agents are useful, for example, in treating or preventing adverse reactions or diseases that may result from, or be associated with, the use of the medical device in the body.
It is known in the art of fabricating medical devices to coat surfaces of the device with coating materials chosen to impart a variety of desirable properties to the device. For example, coatings that include biologically active agents have been applied to stents to provide for drug release and for biocompatibility. Preferably, a biologically active agent remains in a medical device coating during normal handling procedures, but is released from the coating at the desired rate after insertion into a body lumen. However, known medical devices are often difficult to fabricate and/or suffer from not releasing the biologically active agent at the desired rate and/or at the desired time.
Thus, new medical devices, and methods of preparing medical devices that are capable of controlling the release of biologically active agents from their surfaces are needed in the art.